What is the Timber Frame Extension Cost Per m2 in 2021? | Checkatrade
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Timber frame extension cost per m2

Lightweight, reliable and cost-effective, timber has become a popular choice for homeowners building extensions. What’s more, the adaptability of this building material means you can add a timber frame extension to virtually any type of property. Since it’s light and easy to transport, homeowners often opt for offsite prefabricated panel construction which is delivered to the property and installed by a specialist tradesperson. Our practical pricing guide provides an overview of the average timber frame extension cost per m2 to help you budget for the job.

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Timber frame extension cost per m2

Cost provided itemUnitCost
Timber frame constructionPer m2£1,400-£2,400
One storey timber frame extension4m x 5m£28,880
Two storey timber frame extension 8m x 10m£43,320

Ultimately, prices for a timber frame extension will vary greatly depending on the size of the room you have planned. Costs will be based on a per m2 estimation of the plan and will depend on the design, size and type of materials used. Quotes from timber frame building firms will usually range between £1,400-£2,400 per m2 for planning and construction.

However, keep in mind that expensive materials like oak wood will sit on the higher end of the scale at around £2,400. Further, factors such as complexity of the extension and the finish required should factor into your total budget.

Single storey timber frame extension cost

The average cost for a single storey timber frame extension of 4m x 5m is £28,880. Due to the time-savings in site management, timber frames are commonly used on new build homes, allowing the properties to be built faster and sold quicker. With regard to costs, timber frames don’t come with a huge financial advantage, but the quality of the material is better controlled in a factory environment than if it were built directly on site. The primary advantage is the timescales for completing the extension.

Two storey timber frame extension cost

Keeping in mind the average cost of £28,880 for a single storey, a good rule of thumb is to add 50% extra when both storeys have the same size. Using this timber frame extension cost calculator would mean that the total cost for a two-storey timber frame extension would be around £43,320.

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timber frame extension costHow long does it take to build a timber frame extension?

There are a number of variables involved in the timescale of a timber frame extension built. However, on average, you can expect a small extension of around 15m2 to take four to six weeks, while one of 30m2 is likely to take at least six to eight weeks. A large timber frame extension of 60m2 will take between 10-12 weeks.

Do I need planning permission for a timber frame extension?

A timber frame extension is no different to a conventional extension. If the extension doesn’t breach any boundary lines or cause access issues to nearby roads or footpaths, planning permission may not be necessary, but it’s always best to check just in case. If the extension exceeds the criteria set by your local council, you’ll need to make an application for planning permission. 

How do I get started on building an extension?

The first step will be to draw up the plans for your extension. An architect can help to put your ideas on paper, even if they aren’t well versed in timber structures. A specialist contractor will then take your traditionally drawn plans and engineer these into a timber frame kit that will work.

Next, you’ll need to round up a list of tradespeople to help with the project. As well as the timber frame contractors, you will need:

  1. A plumber
  2. An electrician
  3. A joiner
  4. A roofer
  5. A plasterer
  6. A painter/decorator.

two storey timber frame extension cost

It’s worth keeping in mind that architects tend to charge a percentage on the final cost of your extension. So, if for example, your extension comes to a total of £28,880, the cost of an architect will be around £2,888.

Key takeaways for building a timber frame extension

  • The average cost of a single-storey timber frame extension of 4m x 5m is £28,880.
  • Get three detailed quotes and go over them with your designer to ensure you are comparing on a like for like basis.
  • Don’t just use the big firms that advertise in the renovation/house building magazines – there are lots of small firms if you look locally.
  • Always have a contingency budget of around 10% to deal with any unforeseen circumstances.
  • Remember to budget for any additional external works including paving, decking and landscaping.

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